Description: <p><b>Polyphenols</b> are a large and structurally diverse family of plant-derived phenolic compounds characterized by multiple phenolic hydroxyl groups and encompassing major subclasses including flavonoids, phenolic acids, stilbenes, lignans, and tannins. They occur widely in fruits, vegetables, herbs, tea, coffee, cocoa, and medicinal plant extracts. Polyphenols exhibit broad biological activity involving redox regulation, inflammatory signaling, kinase pathways, apoptosis, cell-cycle control, angiogenesis, metabolism, and epigenetic regulation. In cancer models, many polyphenols inhibit proliferation, promote apoptosis or senescence, suppress invasion and angiogenesis, and can alter sensitivity to chemotherapy or radiotherapy. Effects are highly compound-, dose-, and context-dependent; antioxidant activity in normal tissues may coexist with pro-oxidant ROS induction in cancer cells. Oral bioavailability is frequently limited by poor absorption and extensive intestinal, hepatic, and microbial metabolism, making high-concentration in-vitro findings difficult to extrapolate directly to human systemic exposure.</p>
<p><b>Polyphenols</b> — broad umbrella class of plant-derived phenolic compounds.</p>
<ul>
<li><b>Flavonoids</b>
<ul>
<li>Flavones
<ul>
<li>Apigenin</li>
<li>Luteolin</li>
</ul>
</li>
<li>Flavonols
<ul>
<li>Quercetin</li>
<li>Kaempferol</li>
<li>Fisetin</li>
</ul>
</li>
<li>Flavan-3-ols
<ul>
<li>Catechin</li>
<li>Epicatechin</li>
<li>EGCG</li>
</ul>
</li>
<li>Flavanones
<ul>
<li>Hesperetin</li>
<li>Naringenin</li>
</ul>
</li>
<li>Isoflavones
<ul>
<li>Genistein</li>
<li>Daidzein</li>
<li>Formononetin</li>
</ul>
</li>
<li>Anthocyanins
<ul>
<li>Cyanidin</li>
<li>Delphinidin</li>
<li>Pelargonidin</li>
</ul>
</li>
<li>Chalcones
<ul>
<li>Isoliquiritigenin</li>
<li>Licochalcone A</li>
<li>Xanthohumol</li>
<li>Isobavachalcone</li>
</ul>
</li>
</ul>
</li>
<li><b>Phenolic acids</b>
<ul>
<li>Hydroxybenzoic acids
<ul>
<li>Gallic acid</li>
<li>Protocatechuic acid</li>
<li>Ellagic acid</li>
</ul>
</li>
<li>Hydroxycinnamic acids
<ul>
<li>Caffeic acid</li>
<li>Ferulic acid</li>
<li>p-Coumaric acid</li>
<li>Chlorogenic acid</li>
<li>Cynarin</li>
</ul>
</li>
</ul>
</li>
<li><b>Stilbenes</b>
<ul>
<li>Resveratrol</li>
<li>Pterostilbene</li>
</ul>
</li>
<li><b>Lignans</b>
<ul>
<li>Secoisolariciresinol</li>
<li>Matairesinol</li>
<li>Enterolactone</li>
<li>Enterodiol</li>
</ul>
</li>
<li><b>Tannins</b>
<ul>
<li>Hydrolyzable tannins
<ul>
<li>Gallotannins</li>
<li>Ellagitannins</li>
</ul>
</li>
<li>Condensed tannins
<ul>
<li>Proanthocyanidins</li>
</ul>
</li>
</ul>
</li>
</ul>